48 D.G. Jones
Unfortunately, this approach does not prove helpful in dealing with the
early embryo. This is because the timing of brain birth is probably not
until as late as 24–36 weeks (Gertler 1986 ; Burgess and Tawia 1996 ) in
terms of the presence of an integrated neural organization to serve as the
substratum from which self-consciousness and personal life subsequently
emerge (Jones 1998 ). Consequently, the notion of brain birth provides
little guidance on how early human embryos should be treated.
The first 14 days of embryonic development have traditionally been
set apart from subsequent stages, on account of their pre-implantation
status and on the possibility of twinning. However, these embryological
features were not generally considered sufficiently distinctive to bestow
a separate classification upon this 14-day period. This situation changed
when the term pre-embryo was derived to designate ‘the entire product
of the fertilized egg up to the end of the implantation stage’; and the
term embryo for ‘that small part of the pre-embryo or conceptus, first
distinguishable at the primitive streak stage, that later develops into the
foetus’ (McLaren 1986 ). McLaren’s view is a reductionist one that pays
too little attention to the role of the support tissues, which are as essen-
tial for biological development of the early embryo as they are for the
later foetus (Jones and Telfer 1995 ). It also overlooks the potential of
ICM cells to produce stem cells and significant features of the future
individual.
It has generally been considered that the blastocyst has moral value
and should be treated with respect. However, it is generally assumed
that such blastocysts are in utero, whereas the blastocysts on which
research is conducted are in vitro—in the laboratory. Consequently, the
4–6-day-old in vitro blastocyst is in an environment in which it cannot
develop further, unless it is implanted in a woman’s uterus (Jones 2005 ).
This suggests there may be a distinction to be drawn between ‘blas-
tocysts within an environment congenial to further development’ as
against ‘blastocysts within an environment hostile to further devel-
opment’ (Jones 2005 , 2006 ). The first situation has the potential of
producing a human individual; the second has no such potential, espe-
cially since research beyond 14 days is currently forbidden. This means
that all blastocysts are not equal biologically when maintained in a
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